Peace River Valley, in northeastern British Columbia, has become known in recent years as a place of hydraulic fracturing for natural gas—"fracking," as it's commonly called. What are the health impacts related to living near fracking sites where contaminants, including volatile organic compounds, are released? To try to answer that question, Élyse Caron-Beaudoin, a postdoctoral researcher at the Université de Montréal Public Health Research Institute, studied a group of pregnant women who live in the area.

High concentrations of muconic acid—a degradation product of benzene (a volatile, toxic and carcinogenic compound)—were detected in the urine of 29 pregnant women who participated in the pilot study. Their median concentration of muconic acid was approximately 3.5 times higher in these women than in the general Canadian population.

In five of the 29 participants, the concentration of muconic acid surpassed the biological exposure index (BEI), a measure developed by the American Conference of Governmental Industrial Hygienists (ACGIH) to protect the health of people in the workplace. Caron-Beaudoin informed the five women of the results and communicated with their attending physicians. Guidelines of acceptable amounts of muconic acid in urine exist only for the workplace; there are none for the general population.

“Although the levels of muconic acid found in the participants’ urine cannot prove beyond a reasonable doubt that they were exposed to high levels of benzene, these results do clearly demonstrate the importance of exploring human exposure to environmental contaminants in natural-gas fracking regions,” said Marc-André Verner, the lead researcher on the study. Verner is a professor at Université de Montréal’s School of Public Health and specializes in toxicological risk assessment.

“Muconic acid is also a degradation product of sorbic acid, which is often used as a preservative in the food industry,” said Caron-Beaudoin. “However, we believe that diet alone is unlikely to explain the concentrations we found in our participants. A more extensive study needs to be conducted with additional measures—to test the air and drinking water, for example—to confirm or refute the results of our pilot study.”

The health impacts of benzene are well-documented. “High exposure to benzene during pregnancy is associated with low birth weight, an increased risk of childhood leukemia and a greater incidence of birth defects such as spina bifida,” said Caron-Beaudoin. “We were therefore very concerned when we discovered high levels of muconic acid in the urine of pregnant women.”

It should be noted that there are multiple routes of exposure to benzene, including inhaling cigarette smoke, filling your car’s gas tank, driving, and drinking benzene-contaminated water.

“Many reports have been written on the contamination of air and water by volatile organic compounds near natural-gas well sites," said Verner, who is also a researcher at the Public Health Research Institute. "Northeastern British Columbia is a region that supports the use of hydraulic fracturing for natural gas. Despite the fact that many chemicals used or emitted by this industry are toxic to humans, no biological monitoring programs have been implemented in the region.”

Why did Quebec researchers lead a study exploring a public-health issue that mainly concerns people in Western Canada? Good question, Caron-Beaudoin replied. "At a conference, Professor Verner and I learned that certain indigenous communities, including the West Moberly First Nations, were concerned about the contaminants released by the many natural-gas sites on their territory, and about how this was affecting people's health. They were looking for researchers to conduct a formal impact study. We expressed our interest, but were very surprised that this kind of study had never been carried out before.”

Among the pilot study's